High speed fork regenerating repeater for telegraph systems



May 5, 1931.

[he race/way J'e/my H. ANGEL ET AL ,302

HIGH SPEED FORK REGENERATING REPEATER FOR TELEGRAPH SYSTEMS Filed 50, 1929 2 Sheets-Sheet 1 26 2a 7b lie/f 2/4 27 May 5, 1931. H. ANGEL ET AL 2 HIGH SPEED FORK REGENERATING REPEATER i 'OR TELEGRAPH SYSTEMS Filed Aug. 30', 1929 2 Sheets-Sheet 7 M w w 7 w m WM 6 u Karma-w (Rte! 21 (sum-T D TA E Patented May 5, 1931 PATENT OFFICE HERBERT ANGEL AND JAMES W. ROBINSON, or Baoo LYN, NEWYoEK, ASSIGN'ORS T THE WEs'rEaN UNION TELEGRAPH COMPANY, on NEW YORK, N.,Y., A CORPORATION I on NEW YORK Y HIGH SPEED FORK BEGENERATING REPEATER FOR TELEGRAPH SYSTEMS Application filed August 30, 1929. Serial No. 389,568.

This invention relates to telegraph systems wherein the telegraph slgnals received over a land line or cable are so attenuated and distorted that the usual telegraph receiver .or-

dinarily cannot respond thereto, so that regeneration of these signals to reproduce the transmitted signals is necessary before they fiow into the'telegraph receiving apparatus.

The main object of our invention is to provide an organization of apparatus and a method of operation which will facilitate the transmission of messages and increase the load carrying capacity of long signalinglines:

Asis known, signals transmitted over a long land signaling line or over an ocean cable are very much attenuated and distorted in shape at the receiving end. As a result,

the amplitude ofa received signal impulse is very small andthe wave shape is very irregular due to this attenuation and distortion. A'considerable portionof the impulse interval is therefore over before the amplitude of impulse is sufiiciently'large to be eifective in operating a receiving apparatus. This lat;

ter portion of the interval during which the current is sufficiently large for operation, amounts to often less than of the entire impulse interval and furthermore may 'occur in different portions of the signal depending on the system and its operating con ditions.- I

, Inasmuch as the wave shape of other por-v tions of the received signal impulse 1S lrregular and undesirable for regenerat1on,1t is desirable that only that portion of the impulse interval which is of a predetermined minimum amplitude be regenerated.

To this end, the repeating apparatus must be arranged not only to be operative only durin an interval e ual to the effective 1n-.

terval noted above, but must also be adjustable so that it may be effective during the interval while the signalis at the desired maximum value. I Furthermore the repeater must be maintainedin synch'romsm so as to invariably select'the proper interval of the impulse for regeneration.

"The rate'of signaling must accordingly be reduced, from that normally possible over a short line, to an amount such that each imof, signaling, however, increases the cost of operation and is therefore an unsatisfactory solution of this problem. r

In order to increase the rate at which signalingmay efi'ectively be'carried on overlong l1nes,.regeneration systems have been developed in which vibrating members, usually of the tuning fork type, are arranged to vie brate in synchronismwith the received signaling impulses, thetines of the fork, as they engage acontact during a cycle of oscillation, generating signal impulses under control of thereceived signal impulses.

1 The period during which the signal impulse is regenerated in such an arrangement, is .limitedto the interval that the tine engages its outercontact. Inasmuch, however,

as the tine engages'the contact only during a .Due, however, to the transient orirregular character of, the attenuated and distorted received signal, it is desirable that the most:

ideal portion of the received impulse, which in most instances is a very small portion of the entire signal impulse, be employed for controlling the circuit closed by the tine in sible under the conditions described above inasmuch as the adjustment of the tine to vary the period of engagement is considera'bly'limited. Furthermore, asthe ampliits outer position. This, however, is not pos- Accordingly, one of the objects of our in vention is to provide means for selecting the best portion of the impulse period and utilizing only that portion for controlling the regenerator. v

A further object of our inventionis to pro vide means for varying the portion of the signal which is to beregenerated over any length from 'zero' length to a. length which is abovethat" which it is desirable to regener ate.

Still a further object of our invention isto provide ifiea'fis for" regenerating any desired portion of the received signals.

Another object of our invention is to provide means for increasing the rate at which signaling may beca'rr'ied' on over-long: 113565.

In order to select the proper impalse e riedfor regeneration, is necessary not only to provide proper apparatus therefor as be described hereinafter, but also to main tain this apparatus in "proper synchronism' and phase with the received signal impulses.-

Heretdrore, tunin for-ks have been maint'ainecl in s ynchr'oni sm by providingcor rearing medium for the fork, an ranged to operate at the same rate as the torn is vibrating, the: correcting medium functieniIT-g t0 V a-I y the amplitude f ibl lfifoii 11]? 8 6'- cordance variations of synch ronism oi the jerk. Such correcting mediums far to Hold the fork syaearonismfor the reason that as the iork vibration is varied; it tends to Waflclif-T'Olh the GO-rP'eCt Viblfifing frequency.

We have discovered that the correcting medium or circuit must be one" in which the; fork" is suddenly arrested and in by asteady unbroken application of the-correc'ting' current, and, -tinder theseconditions; evenwhen received at arelatively high rate of speed, the signals are regenerated and reshaped although'they may be distorted -al-- most beyond recognition.

A cordin ly, a further object of ourve'n-tion. is to' pi' ot id'e means for suddenly arresting or holding check vibr'a' tin'g berg by a steady unbroken application ofa correcting current.

' Vibrating members heretofore HStfd, V1- brate at doubl the line signalii'ig frequency. At such fork frequencies, there is double the. movement during-any one period of time and greater-difliculty is experienced in maintaining synchronous operation than would be the case if the fork were vibrated fat the signaling frequency. According to our invention,-

ation under varyingconditions as w i lk be due scribed hereinafter; and

Figure 8* illustrates a modified organih tion of apparatus for carrying out our tion. I

In Figure 1,v a signaling line 1 extending..-

from a remote transmitting station is connected to primary winding; 2 of a lime receiving relay 8. The line relay 3 is provided, with armature 4e, which operates between marking and spacing contacts connector to:

the negative and positive-terminals of'a 5815* tery respectively through resistances 5 and 6'. Armature 45 is connected over a conductor 7 and through a resistance 8 and key 9 and conductor 10 to contacts 11 and 12. Contacts 11 and 12 are arranged oneither side of a tongue l ca rriedon the-tines of a tuningfo-rh 14-. The tongue 13 which is grounded and in sulated from the tuning, fork by insulation 15, alternately engages the contacts 11 and 12 as the fork 14' vibrates.

The fork 1 4i, of any well known construetion, maintained in vibration in a-p'proxh mate synchronisn'a with received sign'alsxover line 1 by any wellknown means. Inthe present case, the fork is arranged to be vibrated at a rate slightly greater than the signaling frequency and a brake action isperiodica lly applied by magnet 16, one terminal of which is connected to the positive side of battery through resistance 17-, and the other terminal of which is connected through resistance 18- to acontactor 19 which is adapted to be em gaged by one of the tines of the fork. As" shown, the fork is connected to the negative side of battery so that when the tine of the fork-engages contact 1 9, an energizing circuit is completed for-the brake magnet 16 born the positive side of battery through resistance 17 to the negative side of batteryat the fork 14.

Connected 'to' conductor 10 in multiple with the contacts 11 and 12, is a winding 21 of the regenerating relay 22 connected in series with a resistance 23 and an observing galvanometer 24, the purpose of which will be described hereinafter,

a preferred to the winding 33 of the line relay 3. Connected in shunt relation with respect towinding 33 1s a variable condenser 34, one terminal of which is grounded and the other terminal of which is connected to the mid-point between resistances 31 and 32, the function of i this condenser being to delay energization of the winding 33 after the circuit therefor is completed.

The operation of the apparatus thus far described is as follows: It will be assumed that a negative or marking impulse is re ceived over the signaling line 1 from the remote station. This current flows through and energize-s the winding 2 of the line relay 3. At the beginning of the impulse interval, the wave shape of the signal is irregular and the amplitude too small to positively operate armature4. The amplitude of the current rises, however, until it is sufiicient to operate armature- 4 to engage its right hand or marking contact which is connected through resista-nce 5 to the negative side of battery,

During the time while the current ampli tude is growing to a value sufiicient to oper-, ate armature 4, the armature may, as is well known, chatter and uncertainly move to the right hand contact. During this period, however, which is the undesirable portlon of the impulse interval, no regeneration w1ll take place as will be clear from the description to follow.

During the period while armature 4 uncertainly engages its marking contact in. response to a received impulse which, however, is still weak, the tines of the fork 14, if the fork isin s ynchronism with the received signals, will be in its outermost position at.

whichtongue 13 will engage the contact 11. Current will then flow from the negative side of battery through resistance 5, marking contact in engagement with armature 4, conductor 7, resistance 8, switch 9, conductor v10, contactll and tongue 13 to ground.

An instant laterarmature 4 positively engages its marking contact and the tine of the fork starts to move inwardly and tongue 13 circuit-traced above over tongue 13, which it will be noted, short circuited the winding 21, isopened and the current from thenegative side of battery at armature 4 will now flow through the winding 21 of the regenerating relay -22, resistance 23 and galvanometer 24'to ground. 7

Relay winding 21, upon energization, will operate its armature 26 to engage its right hand or marking contact and a marking impulse will thereupon be repeated from the negative side of battery, resistance 27, back contact and armature 26 and over the conductor 28 to the receiving apparatus, or, next line section. A multiple circuit will be completed from the same source of energy through thelocking winding 25 over conductor 30, resistance32 to the winding 33 of the receiving relay 3. The current through winding 33 flows inthe opposite direction from that flowing in winding 2 and accordingly it tends to throw the armature 4 to its opposite position. The ampere turns in the windings 33 are so calculated, however, as to be less than in winding 2 and the armature therefore remains in position as long as current flows through winding 2.

In order to delay the energization of winding 33, the condenser 34 is interposed in a multiple circuit therewith. As is well understood in the art, the condenser connected in parallel with the inductanceincreases the lag of the current in the relay winding and therefore delays the energization of the winding 33, depending upon the adjustment of the condenser 34. 1

The tongue 13 of the fork 14- has now moved through the gap or space between the contacts 11 and 12 and engages its right hand contact 12. As a'result the bypass circuit, traced above, is again completed. However, the regenerating relay 22 is now locked in position and the shunt circuit therefore has no effect thereon. a

It is assumed for the purposeof this illustration, that a second marking impulse, as indicated in igure2, is received during the second impulse period so that armature 4 re mains in engagement with its marking contact when the tongue 13 of fork 14 engages its righthand contact to complete the bypass circuit described above. 3 When now the tongue 13 disengages contact 12 and moves into the gap between contacts 12 and 11, the original energizing circuit for the winding 21 is again completed. The current flows in the same direction andaccordingly this has no further effect other than to maintain armature 26 in engagement with its marking contact which is already held by locking winding 25. When now the tongue engages its left hand contact 11, two complete impulses have been regenerated as illustrated in Figure 3, for transmission over conductor 28.

It will be assumed that the next impulse as illustrated in Figure 2, is a spacing signal in which case positive current will flow through the winding 2. At the moment of reversal when the line curent falls'to zero the energizing current in the winding 33 be- 4 soem' comes effective to accelerate the operation ofthe armature 4 to engage its spacnrgor' left hand contact. At the instant when this signal is received, the tongue 13- as: described above, engages its left hand contact 11 and a bypass circuit is completed from the positive; side of battery at resistance 6* through the tongue 13 and contact 11 bypassing the winding 21. An later and during the best ort-ion oit thesignal interval, the tongue 13 again moves into theg-ap intermediate the contactors' ill; and 12. Current from the jositive side ofbattery" at resistance 6 there ore flows throngl ithe winding 21, which, upon energization, operates its armature 26 toengage its left hand contact connected to positiveside at battery an impulse from the ositive side o fi batter is repeated over the conductor 28'. Sinu'il taneonsl y current from i positive battery flows through} lock n'ig winding" sewer conductor 3'6 to charge the condenser 3land to energize the relay 33-, which thereu on ten-d s to operaterarinatur'e l to its marking contact.

As will be clear from this description the period during which the tongue of the fork isi n the gap position isutilized for rcgeijieratingthereceived signal, In the description to follow, it will be shown that. by this arrangement, the best portion of the signal may be selecte lin the drawings, the air gap between contarts II and 12 are shown rather wide apart for purposes of clearness. These contacts may be adjustable to vary the air gapbe't'wcen any desired limit. By properly norm-wing the air gap, the energizing time for the regenerating relay may be reduced to ero that is, substantially none of the received impulses will be regenerated if the contacts 11 and 12 are brought together, thus completing a permanent bypass circuit, passing the winding 21. As the air gap, however, is widened, the regenerating period is proportionally increased to a time representing the full time of single impulse interval impressed. upon the line.

In regenerating systems, however, the least amount of time that can possibly be used for regenerating the impulses is desirable inas much as the less time used for regeneration, the more efilcient the system, due to the fact that the signalis so distorted that only a very small portion thereof suitable for regenerating pnrposes. V

In Figures to '7, the portions of the signals desirable for regeneration are shown between the vertical lines. i For signals, such in these illustration, the air gap would be adjusted to maintain the tongue in the gap approximately 25% of the signal period, but as already stated, the gap-may be varied to regenerate any portion of the signal from V 0% to 50% or more thereof.

As will be clear from this description, by

the contact itself is used as was heretofore the practice, adjustment of which can be ob tained only by varying the amplitude of vi: bration of the fork and accordingly reducing the efliciency of operation.

Not only is it desirable to be able to se'lea varying roportions of the signals for regeneration, but it is also desirable to determine which portion is to be selected. As shown in Figures 4 to 7 varying portions of the signals mayberegenerated but only the crest of thesignal is desirable for regeneration. In orderto rc eneratethe proper portion of the received signal, it is necessary that the fork tongue 13 be in the gap position at exactly the; interval when'the crest portion of the signal received and to remain in the gap portion the crest continues;

To this end, a condenser 36 is shunted across the switch 9 and cooperates with the remaining portions of the circuit already described to operate the observing galvsnom star 24 for indicating when the best portion of the signal is being regenerated as will appear from the description of the operation to follow.

In order to determine when the crestof the signal is being regenerated, the key lever 9 is removed from its contact thus removing the shunt from around the condenser 36 so as to eXt-end the circuit from the armature 4-; through the condenser 36, winding 21 to the observing galvanometer 24 when not shunted by ton ue 13' on either contact 11 or 12. As the armature 4 now operates between its marking and spacing contacts, impulses are repeated therefrom though the resistor 8-, condenser 36 and either over the shunt path described or through the winding 21 and serving galvanomcter 24. If now during the rising portion of the: impulse interval, the: tongue 13- leaves either contact H or I2, the changing value of current in the con-d netor 7 will flow though the condenser 36- and through the observing galvanometer 24-, and the galvanometer willoperatc in accordance therewith. Deflection of the galx' 'anometer pointer will indicate that an undesirablepertion' of the impulse is being received. If the other hand, the armature {l has moved to engage one or the other of its contacts and the crest of received impulse has been re ceived when the tongue 13 is in the air gap, the condenser will have been fully charged while the tongue 13 was in en agement with either contact 11 or 12. W'licn therefore the tongue 13 is in the gap, no further current will flow in the'conductor through the chair e'd condenser 36 and accordingly there will beno deflection of the-pointer of galvan'onreterQel; V 7

In other words, when the pointer of the" tive side of battery.

galvanometer 24 fails to deflect, this is an. indication that the .proper portion of theimpulseis being regenerated, as deflection of the pointer takes place only ifan improper portionof the impulse is regenerated. -Adjustment of vibration of the fork may now be This phase adjustment 1s accomplished by mechanism now to be described.

The line relay winding 2, it will be noted, is connected in series with a resistance 41, connected in series with a tuned circuit 42, comprising an adjustable condenser 43, resistance44 and phase-correcting relay winding 45, comprising an inductance and controlling an armature-46.

The armature 46 is connected through a resistance 47 to the positive side of battery and operatesbetween two contacts connected to thenegative side of battery. The armature is also connected over conductor 48 to the mid-point of windings 49 and 50. The winding 49 is connected through a resistance 51 to the negative side of battery andjthe winding is connected over a conductor 52 to the inner and outer contacts 60, alternately engaged by one of the tines of fork 14.

' Windings 49 and 50 control an armature53 which operates between contacts of conductors 54 and 55 respectively in turn connected to a switch 56. The switch 56 when in its left cuit from conductor 55 over the same con ductor 57 for controlling brake magnet 16.

In either of these positions, the switch 56 also completes circuits over the alternate conductors 55 and 54 and over conductor 58 to the sounding magnet 59 connected to the posi- Normally the armature 46' moves to its right and left hand contacts in synchronism with the armature 4 of the line relay 2. During the period while armature 46 "is moving from one to the other of its contacts in responseto a received'signal impulse, current from positive side of battery at resistance 47 flows over the-conductor 48 and through winding 49 and resistance 51-to negative battery. If the tine of fork 14 is at this time in engagement with one of its contacts 60, as it should be if it is in proper phase with the signalimpulses, current 'will also flow through the relay winding 50, conductor 52 and over the contact 60 with which the tine of the fork 14 is in engagement to the negative side of battery, the current flowing in winding 50 overcomes the effect of the current in windingf49 and is in a direction to throw the armature 53 to engage its right hand contact. As a result, a circuit is completed from the negative side of battery ,7

through the armature53, conductor 55, switch 56, conductor 58 to the sounder 59, but no circuit 1s completed over conductor 57 inasmuch as th1s conduct-eras connected over conductor 54 to the left hand contact of armature 53.

If on the other hand, the tine of fork 14 is at thls time not'in engagement with one of its contacts, but 1s 1n the air gap therebetween, as

-would' be the case if the fork is ahead of the signal due to its normal higherspeed of operation, the circuit traced above through. the winding 50 isnot completed and only the circuit from the positive side of battery through resistance 47 ,conductor 48, through the winding 49, resistance 51 tonegative battery is completed. In that case, armature 53 is thrown to engage its left handcontactand anenergizing circuit iscompleted to the brake magnet 16, whichis thereupon energized by a continuous brake current andacts as a brake to slow up the vibration of the tuning fork by continuous brake current. This current will continue to flow until the tine has been sufficiently slowed up to be insynchronism again with the received signals, r whereupon a'circuit through winding 50 will be completed during the period while armature 46 is in mid gap position in response to a changed signal as described above and the armature 53 will-again be thrown to its right hand position, opening the circuit of the brake magnet 16.

From the above, it will be clearnow that the tuning fork is driven at a slightly faster rate of speed than the line speed and is quickly arrested -or slowed down by applying'a steady unbroken direct current to the brake magnet until the fork has slowed to proper speed, at which time the slowing down circuit is disconnectedand the fork is again al- 1 lowed to run free until some time when it runs faster than it should whereupon it'is again justable condenser 43. As is well known an 1nductance produces a lag in .the circuit throwing the current a variable amount behind the voltage depending on the value of 1 the inductance, A condenser connected: in

parallel with such an inductance as distinguished froma series connection, will throw the currentstil'l further behind the voltage depending on the value of the capacity. Ac-

circuit including the resistance 44 and: ad-

be made to maintain its tongue 13 inengagement with contacts 11 or 12 at different times in the impulse interval to select-the proper crest portion of the received signals for regeneration.

Reviewing the means for correcting-the forlq it will be noted that the synchronizing relay 45 repeats an impulse over conductor 48, which is always of less time duration than the usual signal, inasmuch as the repeated signal flows only during the period when the armature Kids in the air gap position between its contacts- This makes the correcting impulse'sof shorter time duration than the air gap time of'the fork tine, sot-hat thei mpulse can only be effective during a part of the time that the fork tine is on its contact 11 for-12.

As will now be clear from the above description, not only may the percentage of impulse interval be selected by adjustment of the contacts 11 and 12' to vary theair gap therebetween, but the portion of the crest selected may be varied asshown in Figures to 7 by adjustment of the condenser 43 which adjustment will control the time interval' of a received signal impulse so that the armature 46' will operate between its contacts to in turn control the phase of the tuning fork 14 with respect to the received signals.

The switch: 56' is shown as a double throw switch. When in its left hand positiom-a fixed relation between the operation of armature 46 and the vibration of tlietuning fork is maintained. By throwing the switch 56 to its right hand position, the connections thereto are reversed with respect toathemarking and spacing contacts of the relay '50 so as to shift the checking .circnitsfrom spacing to marking contact, which in turn shifts the moment of impulse regeneration through an angle of 180.

In the above description, the fork'is described as normally vibrating slightly faster than the fundamental line frequency and maintained at true speed by repeatedly slowing it down when it gets beyond a predetermined phase position with respect to the re- .ceived impulse. I The fork may, if preferred, be arrangedto run at exactly-the line frequency and be varied to decrease or increase its rate or vihration in accordance with variations thereof from the. fixed rate. In Figure 8' an arrangement for this kind of correction is shown. The receiving apparatus, being ilar to that described in connection with Figure- 1, is not here disclosed, only that portion of the synchronizing means being shown which is different from that shown in Figure 1 being illustrated. Tuning fork 61 in this system is normally maintained invibration,

operating with one of the tinesof the timing fork and is also connected in multiple over a conductor 66 extending to the right and left hand contacts respectively of armatures 67 and 68151 the relays 69 and 70 respectively. Relay 69v comprises two; windings 71 and 72 and relay 7 0 comprises two windings '73 and 74. .Windings 71 and '73 are connected: in series with resistance 75 to the negative Side of battery and over conductor 7.6 to thcarmnture 77 of the synchronifiing relay 78.. 'Relay 78 is connected in a.- circuit with a re sistance 80 and avariable condenser 81 for adjusting the time when the relay 7:8- is affected by the line impulse: received overthe line 82 as describml in; connection with Figure I. The armature 7 7 is. connected through the resistance 83 to the positive side of battery.

Windings 72 and. 74 are contracted inrmnltipleto the conductor 84 and each winding'in turn extends over the conductors 85'afnd 56, respectively, to the left and right hand contacts of armature 87 of relay 8.8; Relay 6 in turn is connected over conductor 8960 two contacts .90 engaged by the" tuning" "011: in either its inner or enter position.

The fork in this case is adjusted to-mast exactly the, speed of line frequency. When the correcting relay 78 operates'arma nre 77 from its left to its right hand contact in responseto a receivedimpulse and while the armature 77 is in midgap position, current flows from positive side oi battery through the resistance 83, conductorm and through the windings 71 and 73 and resistance 75 to negative battery. Current: may also. flow in multiplethr ngh either the winding 74 to armature 87 or to the winding 72 annatnre 87 depending uponwhetherthe armature 87 is in engagement with its treat 01' back contact. .The relay 88, it il b 0 is energized twice per movement of the tuning fork; that-is, once in its inner-position and again when inits outer position and isdcenergized while the fork icpin mid way tion.

i If them-mature 87 of relay 8.8 is in mi gap position as it should be, the fork having just left a contact when the correcting pulse flows in the conductor 76, described above, neither winding 72 1101' 74: will become energized. The current conductor 7 6. l w-s through thevwindings 71 and 73 and operates LOO 7 right hand contact.

their armatures 67 and 68 respectively to spacing or left hand contacts. In this case, the fork is vibrating at the correct speed and in proper phase relation. A circuit is completed from negative battery over the resistance 68' tongue 68 in engagement with its left hand contact and over the conductor 66 to the magnet 62. This is a nornialcondition when the fork is running at true speed.

through thewinding 71 to overcome the effect of'the current in the winding 71 and the armature 67 is operated to its marking or This is the condition obtained when the fork is running faster than it should and the checking circuit completed over the conductor 66 being now multipled to negative battery over armatures 67 and 68 and resistance 67 and 68, a greater current will flow over this circuit and the increased current in the winding-62 increases the brake action of the magnet slowing up the fork vibration.

If on the other hand, when the correct- 7 ing current flows over conductor 76,'the relay 88 has completely deenergized due to the fact that the tuning fork has moved s'ufli ciently far from the contacts 90 OI the fork to have provided suflicient time for therelay 88 to deenergize, this indicates that the fork is behind the received signal. Deenergization of the relay 88 causes its armature 87 to move to the position shown in the d.rawing,.breaking the circuit through. winding 7 2 and completing the circuitthroughwinding 4C. T he current flowing through winding 71 again becomes effective to move armature 67 into engagement with its left hand contact. The

flow of current from conductor 7 6 th ough the winding 7 4: will produce sutficient'anipere turnsto overcome the ampere turns in O the winding 73 and the armature 68 will.

move to its right hand or marking contact, in which case no current Wlll flow 1n the conductor 66. As a result, the bral're action of the brake magnet 62 will be reduced and the fork will thenincrease its speed of vibration;

Although we have described our invention in connection with a specific adaptationthereof, it will be clear that it has other applications where remote signaling is carried on over synchronizingsystems and may have other embodiments thereof. Thus, although we have described this system in connection with telegraph systems it willbe apparent that it may be used in any signaling systems 65 based on synchronous principle of operation.

Our system possesses many advantages over prior systems. By the arrangement shown, slgnaling may be carried on at considerably increased speed inasmuch as regeneration can be considerably improved over prior systems and the portion of the crest of signal waves to be regenerated can be readily selected by adjustment of the vibration ofthe tuning fork contact and the proportion of the crest to be utilized for regenoration can be selected by adjustment of the contacts.

A greater degree of accuracy may be obtained inasmuch as the tuning fork vibrates at the signal frequency and a sudden unbroken direct current controls the operation of the tuning fork.

o claim! 1 g 1. In a signaling system, a first signaling line, a second signaling line, atuning fork operating between contacts and means contiiolled by said tuning fork for repeating that portion of said signaling impulses received while said tuning fork is in non-contacting position between said contacts.

2. In a signaling system, a first signaling line, a second signaling line, a tuning fork regenerator operating in accordance with impulses received over said first linefor controlling the repeating of said impulses over said second line and means for indicating which portion of a received impulse is re generated, means responsive to received impulses for controlling the rate of vibration of said fork and means forvarying the action of said last mentioned impulse means for variably selecting any portion of said received impulse for regeneration asdetermined by said indicating means.

3. In a signaling system, a first line, a sec ond line, a tuning fork operating between two contacts. a first relay in sa d first line having an armature connected to said contacts, a second relay connected to said armature. in multiple with said contacts whereby said second relay is energized in accordance with the operation .of said first relay when said contacts are disengaged from. said fork. f

a. In a signaling system, a first line, a second line, a tuning fork operating between two contacts, a first relay in said first line having an armature connected to said contacts, asecond relay connected to said armature in multiple with said contacts whereby said second relay is energized in accordance withthe operation of said first relay when said contacts are disengaged from said fork,

relay in accordance with the position of said fork and said other contacts when a signal is received for maintaining a predetermined frequency of vibratlon of said fork.

In a signallingsystem, a first line, .a.sec e, a first relay in said first line comprising a line winding and an accelerating windooera'ti in response to reversals of implus received over said first line, a second relay 'asaid second line having an armature connected to said accelerating winding, means whereby said second relay is operated in accordanc with the operations of said first relay for repeating the received first line impulses over said second line and a condenser connected to the circuit extending from said accelerating winding to the armature of vsaid sccoa l windin-g fer assistingsaid first relay t be reversed when the first line current falls to zc-roat the moment of reversal and for further carsing said first relay to be repeated ly reversed at the fundamental rate of frequency as long the line current remains at In a repeater system, means vibrating at a predetermined frequency, a signaling line, a relay'means in said line, means controlled by said vi rating means for generating impulses in according with the impulses received over said signaling line to which said receiving relay means responds and means responsive to variations said vibrating means from the frequency of said signaling impulses for applying a correction thereto, said last means continuing as long as said vibrating means remains out of synchronism.

7. In a repeater s ystenna tuning fork maintained in vibration at a predetermined frequency, magnetic means for controlling said tuning fork and means controlled by variations of said tuning fork from the predetermined frequency for applying an energising current continuously to said magnetic means to change its frequency, said cont-rolled means continuing in operation during the time that said correction is applied. 7

8. In a repeater system, a tuning fork, a controllertherefoiaa Signaling line, a relay means in said line, arepeater'line, means controlled by said tuning fork for repeating impulses over-said repeater line in accordance with the impulses received over said signaling line .to which said receiving relay means respends, means responsive to variations of s fork from .a predetermined rate of vibration for applying a continuous energizing curren-tto v said controller.

v9. In a repeater system, a vibrating member maintained in vibration ata predetermined frequencyand a brake magnet for decreasing the-rate of vibration of said vibrating member. means for applying a continuous energizing current in accordance with the variatic-us of said member from a predetermined frequency to said brake magnet to increase the brake action thereof during the time that a correction is applied.

10. In a signaling system, a vibrating member vibrating at a predetermined frequency,

means controlled by received signaling impulses, second means jointly .COlltlOll-QdbYfltllC rate of vibration of said vibrating member and by said first means for varying the freq-ucncycf vibration .of said vibrating member,

mentioned means for varying-the vibration of sa-idvibrating means solely under control of said vibrating member,

12. In a signalling system, a first line, a second line, a first relay in said first linecomprising .a line winding and an accelerating winding operating in response, to reversals of impulses received over said first line, a second relay in said second line having an armature connected to said accelerating winding, means whereby said second relay is operated in accordance with the operations of said first relay for repeating the received first line impulses over said second line and a condenser connected to the circuit extending from said accelerating winding to the armature of said second winding for assisting said first relay to be reversed when the first line current falls to mro at the moment of reversal.

13. In a signalling system, a first line, a I

second line, a first relay in said first line comprising a line winding and an accelerating winding operating in response to reversals of impulsesreeeived over said first line, a

second relay in said second line having an armature connected to said accelerating winding, a vibrating member opera-ted in synchronism with received impulses for operating said second relay in accordance with the operations of said first relay for repeating the received first line impulses over said second line anda condenser connected to the circuit extending from said accelerating winding to the armature of saidsecondwinch ing for assisting said first relay to be reversed when thefirstline current falls to zero at the moment of reversal and for further causing said first relay to be repeatedly reversed at the fundamental rate of frequency as longas the line current remains at zero.

14. A signaling system comprising an incoming line, a receiving relay connected to the incoming line, a re eating regenerating relay operating in response to the movements of the armature of the receiving relay, means for indicating the portions of the signal impulses being repeated, and means for variably selecting any desired signal portion determined by said indicating means.

15. A signaling system, comprising an incoming line, a receiving relay, and a signal recording or retransmit-ting means embodying a repeating relay and a vibratory device, said repeating relay being under the joint control of said vibratory device and said receiving relay, said vibratory device having a member operating between a pair of contacts adjustable toward and from each other to determine the portion of the signal impulses being repeated.

16. A signaling system, comprising an incoming line, a receiving relay connected thereto, signal recording or retransmitting mechanism embodying a repeating relay responsive to said receiving relay and a vibratory device operating between adjustable contacts to determine the portion of each signal impulse to be repeated, and means responsive to a variation in the phase relation of the vibratory device with respect to the incoming signals for applying a continuously operating adjustment during said variation.

17. A. signaling system as set forth in claim 16, said signal-impulses being repeated while said member is in non-contacting position between said contacts.

In testimony whereof we atfix our signa- 

